Improved telegraphic cable



"Tr-fm @fwn/intim@ i Ni niifiiine @VE TL Specification forming pti-rt ofLetters Patent No. Qf-h dated Gctober il, i559.

e all whom it may concern.'

Ide it known that l, WM. H. JOHNSON, of Springiehl, in the countyot'Hampden end State ot' Massachusetts, have invented certain improvementsin Electric Conductors for Trnnsinitting lelegrnphic Sign-els, of which'the following is e full, elettr, and exact description, reference beinghed to the accompanying drawings, making part of this specification, inwhichiiigure l represents aportion of ai submerine telegraph-cable, partof the coating being;`

' broken away to-show the wires within 5 Fig. L,

e trzinsverse section ot' the seine; Fig. 3, the seine enlarged.

Hcretot'ore solid wire hns been used es u conductor for tinnsinittingtelegrophic nies- Snilges, but it hns been 'found that when its surfaceis exposed to the action oi' the elements, particularly of writer,thai-t the current of eleotricity is weakened by being' carried o` freinthe surtnce of the wire. ilo remedy, in n ine isure, this defect, thewire hns been coe-ted with vu-rious ninteriuls ot' n less elec ricconductibility than the wire itself. This precenion in subniurinetelegrnphing seems to be sbsolutely essential, ns the wire wouldotherwise be in consta-nt ninliinniedinte contact with thesurroundingwaiter; but on land routes it is generally oinitted onaccount. ofthe additional expense of constructing;` the line, andtheplain vireis found to answer very well for the transmission of messagesduringthe ordinary conditions ot' the surroiuiding` atmosphere. l Butwhen the uncouti-d wire is exposed (es fre quontly occurs) to storms nudpeculiar electric changes of the atmosphere, the electric current iscerried oli' from the snrt'aceof thewire to such an extent ns tointerrupt nud frequently entirely prevent the transmission ot' messagesover the line. Further, the plain wire is found to not better in theordinary conditions oi' the atmosphere then theft which is coated 'withguter-perche oiother ninterials, showing that n clear und unobstructedsurf-nce gives e niore ei'licient action to the conductor.

'io obtain such a surface und yet be eble toniej; be simply coated withseine materiel., suon as guttziperche, to. pictos-3 its outer surfacefrom being effected by the'externel innences which nre usually found tobe detri inen tel. to the et'ticient 'uc-tien cf/ an electro telegrnphicconductor, while its inner surface remains perfect-ly free; or, forsubmarine telegrnphing, it muy forni part ot' e cable, such as is reprelsented in Figs. l, 2, und 3 ot' the drawings, in

u is the tube or conductor; b, 2i coating of guita-perche, whichsurrounds it. @Ver this nre placed the wires c, which lie lponzilel tothe exis ot' the tube, and ere held in position duringl the constructionof the ceble by u thin wire7 d, which is wound spirally around thein.Ehe outer coating, f, of guita-perche, isthen .npplieih which binds thewhole into one solid rllhere nre-other forms of conductor which een beused und the suine end be obtained. cannot here enumerate theni all, butwill describe one, iis shown in section, Fig. yrlhe solid wii e B hnsprojections 2 and recesses or `grooves 5 nlong its length. The coatingjmay bedxewn over-the wire in e.. thin sheet or tube or be wound aroundit, when the wire will be protected, while the-surface in the grooves 3

